Data centers and their cooling systems have been evolving for many years as engineers continually work on reducing energy costs and improving reliability and sustainability. Advances in the reliability and tolerance to environmental conditions of data center equipment have led many large-scale data centers to take full advantage of the outdoor ambient conditions to provide cooling for the servers and other critical network equipment to lower the PUEs for these facilities. Systems using airside economizing and evaporative cooling have consistently delivered PUEs in the 1.14-1.3 range.
Data centers are unique building applications for airside economizing. The heat created by the data center equipment and the 24/7/365 operation allows airside economizing to be the primary cooling source for a significant number of operating hours. Depending on the location of the data center, airside economizing can save 30%-80% on cooling energy vs. chiller-based cooling systems. One problem that data center design engineers face in utilizing airside economizing is the extreme temperature stratification that can occur in large air-handling unit plenums when the warm return air from the hot aisles fails to mix with colder outdoor air being drawn in to provide cooling and the correct supply air temperature.